enthalpies of solution Flashcards
1
Q
what 2 things happen when an ionic lattice dissolves in water
A
1) the bonds between the ions break to give free ions - endothermic
2) bonds between the ions and water are made - exothermic
2
Q
why do water molecules bond to the ions
A
because oxygen is more electronegative than hydrogen so it draws electrons towards itself creating a dipole. this means the positive hydrogen atoms can create bonds with the negative ions and the negative oxygen atoms can form bonds with the positive ions.
3
Q
what is the rule for susbtances for if substances dissolve or not
A
substances will only dissolve if the energy released is roughly the same or greater than the energy taken in, so soluble substances tend to have exothermic enthalpies of solution (energy released)
